The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
In automotive vehicles having manual transmissions, a driver typically actuates a clutch pedal to disengage a clutch. With the clutch disengaged, the driver selects a desired transmission gear with a gear shifter. For example, the driver may select a higher gear (i.e. during an upshift) or a lower gear (i.e. during a downshift). When the gear shifter is in a position corresponding to the desired transmission gear, the driver releases the clutch pedal to reengage the clutch.
Generally, an engine speed before and/or during upshifts and downshifts is not equivalent to a speed of an input shaft of the transmission after the desired transmission gear is selected. For example, during a downshift, selecting a lower gear causes the speed of the input shaft to increase significantly. In contrast, with the clutch disengaged, the engine speed decreases significantly. Consequently, when the clutch is reengaged, the speed of the input shaft is significantly greater than the engine speed. The clutch is subjected to increased stress as a result of absorbing load associated with the difference between the engine speed and the input shaft speed, and driving feel is negatively affected. Similarly, during an upshift, the engine speed decreases significantly, and reengaging the clutch forces the clutch to absorb a load associated with the difference between the engine speed and the input shaft speed.
Some drivers may perform heel-toe shifting to mitigate effects of upshifting and downshifting (i.e. speed matching). For example, while decelerating rapidly with the clutch disengaged, a driver may apply the brake with an inner portion of the foot while simultaneously applying the accelerator with an outer heel portion of the same foot. With the clutch disengaged, relatively slight pressure on the accelerator causes a significant increase in the engine speed. When the desired transmission gear is selected and the clutch is reengaged, the engine speed may be more appropriately matched to the input shaft speed. However, driver initiated speed matching such as heel-toe shifting relies on driver skill and the ability of the driver to accurately predict the desired engine speed.